package teste;

/*
 * @(#)MergeSortAlgorithm.java	1.0 95/06/23 Jason Harrison
 *
 * Copyright (c) 1995 University of British Columbia
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL purposes and without
 * fee is hereby granted provided that this copyright notice
 * appears in all copies. Please refer to the file "copyright.html"
 * for further important copyright and licensing information.
 *
 * UBC MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. UBC SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 */

/**
 * A merge sort demonstration algorithm SortAlgorithm.java, Thu Oct 27 10:32:35
 * 1994
 * 
 * @author Jason Harrison@cs.ubc.ca
 * @version 1.1, 12 Jan 1998
 */
public class MergeSortAlgorithm extends SortAlgorithm {
	private void sort(int a[], int lo0, int hi0) throws Exception {
		int lo = lo0;
		int hi = hi0;

		if (lo >= hi) {
			return;
		}
		int mid = (lo + hi) / 2;

		/*
		 * Partition the list into two lists and sort them recursively
		 */
		sort(a, lo, mid);
		sort(a, mid + 1, hi);

		/*
		 * Merge the two sorted lists
		 */
		int end_lo = mid;
		int start_hi = mid + 1;
		while ((lo <= end_lo) && (start_hi <= hi)) {

			if (a[lo] < a[start_hi]) {
				lo++;
			} else {
				/*
				 * a[lo] >= a[start_hi] The next element comes from the second
				 * list, move the a[start_hi] element into the next position and
				 * shuffle all the other elements up.
				 */
				int T = a[start_hi];
				for (int k = start_hi - 1; k >= lo; k--) {
					a[k + 1] = a[k];

				}
				a[lo] = T;
				lo++;
				end_lo++;
				start_hi++;
			}
		}
	}

	public void sort(int a[]) throws Exception {
		sort(a, 0, a.length - 1);
	}
}
